Page 1Page 2Page 3Page 4Page 5Page 6Page 7Page 8Page 9Page 10Page 11Page 12Page 13Page 14Page 15Page 16Page 17Page 18Page 19Page 20Page 21Page 22Page 23Page 24Page 25Page 26Page 27Page 28Page 29Page 30Page 31Page 32J U L Y / A U G U S T 2 0 1 6 POTATO GROWER 17 growers and we are assisted by Dr. Gary Secor in this work. A study to determine the effects of 2,4-D as a weed suppres- sant and effect on yield in white-, rus- set-, and yellow-skinned cultivars is being conducted in Grand Forks and Inkster. This work is supported by a North Dakota Minor Crop Use Fund grant. Inkster, North Dakota Two herbicide trials are established to evaluate different herbicide formula- tions of metribuzin and rimsulfuron. We are also working on a project funded by the NPPGA and Minnesota Area II to reduce phosphorous acid injury in pota- to and evaluate the effectiveness of phosphorous acid. Dr. Neil Gudmestad is working in conjunction with us on this project. Crystal, North Dakota A variety trial at the farm of Dave and Andy Moquist (O.C. Schultz) has 21 red- skinned and 10 yellow-skinned vari- eties. We are evaluating these for yield, blemishes, and storability. University of Minnesota, Department of Soil, Water and Climate Dr. Carl Rosen, UMN In 2016, six studies conducted at the Sand Plain Research Farm in Becker are outlined. Some are continuation of studies initiated in previous years. The overall goal of this research is to improve nutrient management for pota- to production on irrigated sandy soils. The objectives and brief descriptions of these studies are as follows: Effects of Nitrification and Urease Inhibitors on Potato Yield and Quality, Nitrate Leaching, and Nitrous Oxide Emissions The compound 3,4 dimethylpyrazole phosphate (DMPP) has recently been developed and introduced as a nitrifica- tion inhibitor for urea. Few studies have been conducted with DMPP on potato and comparisons with other urea prod- ucts such as Super U and urea coated with Guardian are limited. Super U is a mixture of dicyandiamide (DCD), a nitrification inhibitor and N-(n-butyl) thiophosphoric triamide (NBPT), a ure- ase inhibitor. Guardian is a DCD formu- lation that can be coated onto urea. The primary objective of this study is to determine the effectiveness of DMPP as a nitrification inhibitor for potatoes. A secondary objective is to determine if nitrate leaching and nitrous oxide emis- sions can be reduced with DMPP. This is the second year of a two-year study being conducted at the Sand Plain Research Farm in Becker. A series of twelve treatments comparing conven- tional N management with DCD alone, DMPP alone, DCD + NBPT, and DMPP + NBPT are being tested. Nitrate leaching, nitrous oxide emissions, soil nitrate, and petiole nitrate are being monitored through the season. Evaluation of Polyhalite as a Potassium, Magnesium, Calcium and Sulfur Source for Potato Yield and Quality Polyhalite is a sulfate form of potassium, calcium and magnesium manufactured by Sirius Minerals. The objective of this third year study is to evaluate polyhalite on tuber yield and quality of Russet Burbank potatoes. Treatments will com- pare muriate of potash (MOP) with and without S, Ca, and Mg or in blends of polyhalite with MOP based on potash recommendations for Russet Burbank potatoes in Minnesota. The study will be conducted at Becker, MN on a low S, K, Mg, and Ca soil. Petioles samples will be collected during the season and ana- lyzed for nitrate-N, P, K, Ca, Mg, and S. Soil samples to the 6-inch depth will be collected before planting and after har- vest and analyzed for K, Ca, Mg, and SO4-S. Effect of Late-season Boron Applications on Potato Quality Boron is an important essential element that plays a significant role in the integrity of the plant cell wall, where it binds pectins together, and in calcium absorption and sugar transport. In these roles, boron availability is vital to tuber internal quality and storability, as well as yield. The amount of boron needed by plants is relatively low. Generally, 2 lbs B/A is recommended as a preplant application on low B testing soils. However, B is susceptible to leaching and may be at low levels by tuber bulk- ing. Boron at higher applications rate such as 4 lbs B/A can be toxic and actu- ally has herbicidal effects at these rates. Circumstantial evidence suggests that late season boron can enhance tuber maturity by promoting stem detach- ment and lowering reducing sugars such as glucose. However, replicated trials evaluating late season boron applica- tions have not been conducted in the Upper Midwest. The overall objective of this study is to determine the effect of late season boron applications on tuber quality of Alpine potatoes. The study will be conducted at the Sand Plain Research Farm in Becker, MN - The soil is Hubbard loamy sand, which is typical of the soil used for irrigated potato pro- duction in many parts of the state. Alpine potatoes were selected for this study because stems often remain on the tuber at harvest. Six treatments will be evaluated: 1) a control, 2) 2 lb B/A